Maybe Springfield hasn't made any 10 round magazines for them yet? That's the only reason I could think of. Plus, with the incompetents that run our state government agencies, things move rather slowly. It will probably be awhile before they get around to getting it on the CA approved list.

I don't really know, but in my opinon CA is kinda weird on the way they look at many things.

It could be the XDM's increased capacity (9mm mag hold's 19 +1) , but that could be fixed with shorter mags.

Probably not shorter mag unless they made the whole gun smaller or at least grip shorter, but if they made the follower in the mag half as long as the current mag length it would reduce the mag capacity to 9 or 10 rounds. Or they might be able to make a single stack mag that only holds 10 rounds. They would probably have to adjust the mag and mag channel in the grip some way to prevent follower and mag spring switch out with those that are legal in the free world.

I looking to try that gun out at the range as a possible choice for my first handgun.
I really liked the look of it. Now I guess ill check out the xd instead.

So far I haven't found any info that talks about there being any changes that dramatically
change the perfomance between the xd and xdm, though I've seen that some say they've shot better with the xdm.
But ofcoarse there are probably others who feel the opposite.